U.S. patent number 9,913,811 [Application Number 15/186,795] was granted by the patent office on 2018-03-13 for hydroxynaphthoquinone compounds for treatment of non-small cell lung cancer.
This patent grant is currently assigned to Macau University of Science and Technology. The grantee listed for this patent is Macau University of Science and Technology. Invention is credited to Xing-Xing Fan, Lai Han Leung, Xia Li, Liang Liu.
United States Patent |
9,913,811 |
Liu , et al. |
March 13, 2018 |
Hydroxynaphthoquinone compounds for treatment of non-small cell
lung cancer
Abstract
A compound suitable for treating EGFR-dependent non-small cell
lung cancer exceptionally inhibits activity of the EGFR kinase, in
particular in EGFR-dependent non-small cell lung cancer with
intrinsic or acquired resistance against at least one EGFR
inhibitor. Methods for inhibiting EGFR kinase activity in non-small
cell lung cancer cells which harbor an abnormality in the EGFR gene
and for targeting cancer cells harboring an abnormality in EGFR
gene by contacting EGFR-dependent non-small cell lung cancer cells
with said compound are also provided. The compounds allow for an
advantageous inhibition of the EGFR kinase activity and induction
of apoptosis of the non-small cell lung cancer cells with
abnormality in the EGFR gene. Hence, said compounds represent a
highly promising treatment option for patients harboring
EGFR-dependent cancer.
Inventors: |
Liu; Liang (Taipa,
MO), Leung; Lai Han (Taipa, MO), Li;
Xia (Taipa, MO), Fan; Xing-Xing (Taipa,
MO) |
Applicant: |
Name |
City |
State |
Country |
Type |
Macau University of Science and Technology |
Taipa |
N/A |
MO |
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Assignee: |
Macau University of Science and
Technology (Taipa, MO)
|
Family
ID: |
60661036 |
Appl.
No.: |
15/186,795 |
Filed: |
June 20, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170360721 A1 |
Dec 21, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K
31/122 (20130101) |
Current International
Class: |
A61K
31/122 (20060101) |
Field of
Search: |
;514/7.6,19.3,738 |
Foreign Patent Documents
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WO 2013/152186 |
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Oct 2013 |
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WO |
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Other References
Guo; Zhong Xi Yi Jie He Za Zhi; Oct. 1991; 11(10):598-9, 580)
(abstract). cited by examiner .
Lan; Cell Biochemistry and Biophysics; 2014, 70, 1459-1467. cited
by examiner .
Tian; Bioscience Reports; 2015, 35, e00189, doi
10.1042/BSR20150002; published on Feb. 27, 2015. cited by
examiner.
|
Primary Examiner: Bakshi; Pancham
Attorney, Agent or Firm: Renner Kenner Greive Bobak Taylor
& Weber
Claims
The invention claimed is:
1. A method of treating a subject suffering from EGFR-dependent
non-small cell lung cancer comprising administering an effective
amount of a hydroxynaphthoquinone compound of Formula (I) or a
pharmaceutically acceptable salt, solvate or anhydrate thereof to
the subject: ##STR00019## wherein R is selected from --H, --OH,
##STR00020## wherein the EGFR-dependent non-small cell lung cancer
have an intrinsic or acquired resistance against at least one of
gefitinib, erlotinib and/or afatinib.
2. A method of inhibiting EGFR kinase activity in non-small cell
lung cancer cells harboring an abnormality in the EGFR gene
comprising administering an effective amount of a
hydroxynaphthoquinone compound of Formula (I) or a pharmaceutically
acceptable salt, solvate or anhydrate thereof: ##STR00021## wherein
R is selected from --H, --OH, ##STR00022## to a subject suffering
from EGFR-dependent non-small cell lung cancer, wherein the
non-small cell lung cancer cells have an intrinsic or acquired
resistance against at least one of gefitinib, erlotinib and/or
afatinib.
3. The method of claim 1 or 2, wherein the compound is a compound
of Formula (II): ##STR00023##
4. The method of claim 1 or 2, wherein the compound is a compound
of Formula (IIa): ##STR00024##
5. The method of claim 1 or 2, wherein the non-small cell lung
cancer is an adenocarcinoma.
6. The method of claim 1, wherein the subject is a human and
wherein the non-small cell lung cancer comprises cancer cells
harboring an abnormality in the EGFR gene resulting from at least
one of an exon 19 deletion and/or an exon 21 substitution.
7. The method of claim 6, wherein the subject is a human and
wherein the cancer cells harboring an abnormality in the EGFR gene
have an intrinsic or acquired resistance at least against gefitinib
and/or erlotinib.
8. The method of claim 7, wherein the abnormality in the EGFR gene
results from at least one of E746-A750del deletion in exon 19
and/or T790M substitution in exon 20.
9. The method of claim 2, wherein the subject is a human and the
EGFR-dependent non-small cell lung cancer cells harbor an
abnormality in the EGFR gene resulting from at least one of an exon
19 deletion and/or exon 21 substitution and wherein the
EGFR-dependent non-small cell lung cancer cells have an intrinsic
or acquired resistance at least against gefitinib and/or
erlotinib.
10. The method of claim 9, wherein the abnormality in EGFR gene
results from at least one of E746-A750del deletion in exon 19
and/or T790M substitution in exon 20.
11. The method of claim 1 or 2, wherein the compound is
administered in form of a pharmaceutical composition comprising the
compound and at least one pharmaceutically acceptable excipient
selected from at least one of a diluent, a filler, a binder, a
disintegrant, a lubricant, a coloring agent, a surfactant or a
preservative.
12. A method of targeting non-small cell lung cancer cells
harboring an abnormality in the EGFR gene comprising the step of
contacting said cells with a hydroxynaphthoquinone compound of
Formula (I) or a salt, solvate or anhydrate thereof: ##STR00025##
wherein R is selected from --H, --OH, ##STR00026## wherein the
non-small cell lung cancer cells have an intrinsic or acquired
resistance against at least one of gefitinib, erlotinib and/or
afatinib.
13. The method of claim 12, wherein apoptosis of the non-small cell
lung cancer cells is induced.
14. The method of claim 12, wherein the non-small cell lung cancer
cells are from an adenocarcinoma.
15. The method of claim 12, wherein the abnormality in the EGFR
gene results from at least one of an exon 19 deletion and/or an
exon 21 substitution and wherein the non-small cell lung cancer
cells harboring an abnormality in the EGFR gene have an intrinsic
or acquired resistance at least against gefitinib and/or
erlotinib.
16. The method of claim 15, wherein the compound has an IC.sub.50
on the non-small cell lung cancer cells harboring an abnormality in
the EGFR gene of at most 5 .mu.M and an IC.sub.50 on non-cancerous
lung cells being at least 2 times higher than the IC.sub.50 on said
non-small cell lung cancer cells.
17. The method of claim 12, wherein the compound is used in a
concentration of at least 1 .mu.M.
18. The method of claim 12, wherein the compound is a compound
having Formula (II): ##STR00027## and wherein the concentration of
the compound of Formula (II) is at least 2 .mu.M.
19. The method of claim 12, wherein the compound is a compound
having Formula (IIa): ##STR00028## and wherein the concentration of
the compound of Formula (IIa) is at least 3 .mu.M.
20. The method of claim 19, wherein the cancer cells are contacted
with the compound for at least 12 h.
Description
TECHNICAL FIELD
The present invention relates to the administration of a
hydroxynaphthoquinone compound and its effect on subjects with
EGFR-dependent non-small cell lung cancer. More specifically, the
present invention is directed to a method comprising administering
a hydroxynaphthoquinone compound for treating a subject suffering
from EGFR-dependent non-small cell lung cancer. The present
invention further provides a method of inhibiting EGFR kinase
activity in non-small cell lung cancer cells harboring an
abnormality in EGFR gene and a method for targeting cancer cells
from non-small-cell lung cancer harboring an abnormality in EGFR
gene.
BACKGROUND OF INVENTION
Lung cancer is the leading cause of cancer-related mortality in
China and the world, wherein non-small cell lung cancer (NSCLC), in
particular NSCLC adenocarcinoma, accounts for the majority of all
cases. More specifically, NSCLC is the dominate type of lung cancer
with about 85% among all lung cancers.
Over the past decade, it has become evident that subtypes of NSCLC
can be further defined at the molecular level by recurrent "driver
mutations" that occur in oncogenes like tyrosine kinases. There are
more than 90 kinds of receptor tyrosine kinases which are related
to NSCLC. EGFR mutations represent the most common type of driver
mutations for NSCLC. It is assumed that about 10% Caucasian
patients and 30-40% East Asian patients with NSCLC harbor EGFR
mutations increasing the activity of EGFR leading to
hyperactivation of the signaling pathways downstream to EGFR (e.g.
Cross, D. A. et al., Cancer Discovery, 2014, 4(9):1046-1061).
EGFR belongs to a family of receptor tyrosine kinases, namely the
ErbB family, a subfamily of four closely related receptor tyrosine
kinases: EGFR (ErbB-1), HER2/c-neu (ErbB-2), Her3 (ErbB-3) and Her4
(ErbB-4) (Zhang H, et al., J. Clin. Invest. 117 (August 2007) (8):
2051-2058). EGFR is located on the surface of the cells and is
activated by binding of specific ligands and dimerization, which
stimulates its intrinsic intracellular protein-tyrosine kinase
activity and anti-apoptotic and growth-stimulating pathways
downstream to EGFR involving, for example, the phosphoinositide
3-kinase (PI3K)-AKT pathway, the STAT pathway and the MAPK pathway.
This includes transautophosphorylation of some tyrosine (Y)
residues in the C-terminal domain of EGFR, which include Y992,
Y1045, Y1068, Y1148 and Y1173 (Herbst R S (2004). Int. J. Radiat.
Oncol. Biol. Phys. 59 (2 Suppl): 21-6.
doi:10.1016/j.ijrobp.2003.11.041. PMID 15142631, Tam I. Y. et al.,
Molecular Cancer Therapeutics, 2009, 8(8):2142-51).
Modern technology has highly improved the efficacy of treatments in
NSCLC, but new challenge comes up, such as chemo-resistance and
cancer relapse (Mulshine, J. L., Lung Cancer, 2003, 41 suppl
1(2):S163-74, Dragnev, K. et al., Expert Opinion on Investigational
Drugs, 2013, 22(1):35-47).
The majority of EGFR mutations are non-overlapping with other
mutations found in NSCLC like KRAS mutations, ALK rearrangement and
the like. Some of the EGFR mutations do not reduce or increase the
efficacy of EGFR inhibitors (tyrosine kinase inhibitors (TKI) of
EGFR) like gefitinib, erlotinib or afatinib (Oda, K. et al., Mol.
Syst. Biol. 1 (1): 2005.0010. doi:10.1038/msb4100014. PMC 1681468.
PMID 16729045, Cross, D. A. et al., Cancer Discovery, 2014,
4(9):1046-1061). Other mutations reduce the efficacy of EGFR
inhibitors or prevent them from working, i.e. are associated with a
resistance against the EGFR inhibitor(s). An example is the T790M
substitution, a point mutation in exon 20 of EGFR, as one of the
mechanisms of resistance against EGFR inhibitors. There are some
similar mutations associated with a resistance against EGFR
inhibitors, which are D761Y, L747S and T854A etc (Li, D et al.,
Oncogene, 2008, 27(34):4702-4711).
A large number of clinical trials and the NCCN guidelines recommend
EGFR inhibitors in patients with EGFR mutations associated with
efficacy or increased efficacy of EGFR inhibitors. Although
preclinical studies have shown encouraging results, resistant
clinical research is not satisfactory (Jackman, D. M. et al., Clin.
Cancer Res. (August 2009) 15 (16): 5267-73.
doi:10.1158/1078-0432.CCR-09-0888, PMC 3219530. PMID 19671843).
This is because a lot of such patients have or have developed a
resistance against EGFR inhibitors in particular due to an acquired
T790M mutation and/or MET gene amplification or other mechanisms.
Thus, mutations usually associated with an efficacy and/or
increased efficacy of EGFR inhibitors often show acquired
resistance against EGFR inhibitors and patients who initially
responded to EGFR inhibitors might eventually experience disease
progression despite continued treatment.
Accordingly, the efficacy of EGFR inhibitors in EGFR-dependent
NSCLC is limited in an increasing number of patients. Thus, further
potent treatment options for treating EGFR-dependent NSCLC are
urgently required. As usual, it would generally be desirable to
provide treatment options including compounds with reduced risk for
side effects and interactions, which compounds can be prepared in a
cost-effective way. Usually, plants and respective ingredients in
plants are suitable to provide such advantageous properties and,
thus, research also focuses on such materials.
For example, Zi Cao, the dried root of Arnebia euchroma, Arnebia
guttata, or Lithospermum erythrorhizon is already used as a
Traditional Chinese medicine with the major component shikonin. The
latter possesses antioxidant effects (Assimopoulou, A. N. et al.,
Food Chemistry (2004) 87 (3): 433-438.
doi:10.1016/j.foodchem.2003.12.017), antimicrobial effects against
Staphylococcus aureus and Staphylococcus epidermidis, wound
healing, antitumor, and antithrombotic properties (Papageorgiou, V.
P. et al., Angew. Chem. Int. Ed. (1999) 38 (3): 270-300.
doi:10.1002/(SICI)1521-3773(19990201)38:3<270:AID-ANIE270>3.0.CO;
2-0). Shikonin has been shown to have anti-cancer activity such as
in prostate cancer, liver cancer or breast cancer and other cancer
cells, but have not been proposed for NSCLC and the specific patent
group with EGFR-dependent NSCLC, respectively.
SUMMARY OF INVENTION
The first aspect of the present invention relates to a method of
treating EGFR-dependent NSCLC by a compound of Formula (I) in a
subject in need thereof, in particular the NSCLC is an
adenocarcinoma.
Namely the method of treating a subject suffering from
EGFR-dependent NSCLC comprises administering an effective amount of
a hydroxynaphthoquinone compound having the structure of Formula
(I) or a pharmaceutically acceptable salt, solvate, or anhydrate
thereof:
##STR00001##
R is selected from --H, --OH,
##STR00002## to the subject.
In particular, the compound has the structure of Formula (II):
##STR00003## and comprises a mixture of compounds of Formula (IIa)
and Formula (IIb) or is a racemate of compounds of Formula (IIa)
and Formula (IIb):
##STR00004##
In particular, the compound administered is one of the compound of
Formula (IIa) or Formula (IIb).
In still another aspect, the present invention refers to a method
of inhibiting EGFR kinase activity in NSCLC cells harboring an
abnormality in the EGFR gene by a hydroxynaphthoquinone compound of
Formula (I) in a subject in need thereof, i.e. comprising
administering an effective amount of the compound of Formula (I) or
a pharmaceutically acceptable salt, solvate, or anhydrate
thereof:
##STR00005## with R as defined above, in particular a compound of
Formula (II) given above, to the subject suffering from
EGFR-dependent NSCLC. In one embodiment, the disease is an
adenocarcinoma.
According to the invention is also the compound of Formula (I),
such as Formula (II), for use in the treatment of EGFR-dependent
NSCLC. Furthermore, the invention refers to the use of the compound
of Formula (I), such as Formula (II), for preparing a medicament
for treatment of EGFR-dependent NSCLC.
The compound of Formula (I), such as of Formula (II), or a salt,
solvate or anhydrate thereof can be administered to the subject in
form of a pharmaceutical composition. Said pharmaceutical
composition further comprises pharmaceutically acceptable
excipients and may additionally contain further active ingredients,
in particular therapeutic compounds for treating NSCLC. The present
invention also refers to the use of the pharmaceutical composition
for inhibiting EGFR kinase activity, such as for suppressing
transautophosphorylation of EGFR kinase, and/or inhibiting the
anti-apoptotic and cell growth stimulating signaling pathway
downstream to EGFR.
The present invention, in another aspect, refers to a method for
targeting NSCLC cells harboring an abnormality in the EGFR gene, in
particular an abnormality in the EGFR gene resulting from at least
one mutation selected from deletions in exon 19, substitutions or
insertions in exon 20, or substitutions in exon 21 of the EGFR
gene, more preferably selected from T790M and/or E746-A750del. Such
mutations can further be associated with, in particular, at least
one of MET gene amplification and/or FGF2 and FGFR1 induction.
Said method of the present invention comprises the step of
contacting said cells with a hydroxynaphthoquinone compound of
Formula (I) or a salt, solvate or anhydrate thereof:
##STR00006## with R as defined above. In particular, the compound
is a compound of Formula (II) given above. Preferably, apoptosis of
the NSCLC cells harboring an abnormality in the EGFR gene is
induced.
The inventors found that the hydroxynaphthoquinone compound
according to the present invention is especially suitable for
treating patients with EGFR-dependent NSCLC and for targeting NSCLC
cells harboring an abnormality in the EGFR gene, respectively, i.e.
cancer and cancer cells with a EGFR mutation, in particular with
intrinsic or acquired resistance against EGFR inhibitors such as
gefitinib, erlotinib and/or afatinib. More specifically, the
inventors found an advantageous inhibitory effect of the
hydroxynaphthoquinone compound on EGFR kinase activity and an
exceptional induction of apoptosis of the NSCLC cells by the
hydroxynaphthoquinone compound. Transautophosphorylation of EGFR
could be advantageously reduced with increased EGFR
degradation.
Other features and aspects of the invention will become apparent by
consideration of the following detailed description and
accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1A shows the cell viability of CCD19 cells after 24 hours
treatment with the compound of Formula (IIa).
FIG. 1B shows the cell viability of H1650 cells after 24 hours
treatment with the compound of Formula (IIa).
FIG. 1C shows the cell viability of HCC827 cells after 24 hours
treatment with the compound of Formula (IIa).
FIG. 1D shows the cell viability of H1975 cells after 24 hours
treatment with the compound of Formula (IIa).
FIGS. 2A, 2B, 2C, 2D, and 2E show Flow Cytometry patterns of H1650
cells having been treated with different concentrations of the
compound of Formula (IIa) and of the control group. FIG. 2A shows a
Flow Cytometry pattern of H1650 cells of the control group. FIG. 2B
shows a Flow Cytometry pattern of H1650 cells having been treated
with 1 .mu.M of the compound of Formula (IIa). FIG. 2C shows a Flow
Cytometry pattern of H1650 cells having been treated with 2 .mu.M
of the compound of Formula (IIa). FIG. 2D shows a Flow Cytometry
pattern of H1650 cells having been treated with 3 .mu.M of the
compound of Formula (IIa). FIG. 2E shows a Flow Cytometry pattern
of H1650 cells having been treated with 4 .mu.M of the compound of
Formula (IIa).
FIG. 2F shows the rate of apoptosis of H1650 cells having been
treated with 1 .mu.M, 2 .mu.M, 3 .mu.M or 4 .mu.M of the compound
of Formula (IIa) of the present invention compared to the control
group.
FIGS. 3A, 3B, 3C, 3D, and 3E show Flow Cytometry patterns of H1975
cells having been treated with different concentrations of the
compound of Formula (IIa) and of the control group. FIG. 3A shows a
Flow Cytometry pattern of H1975 cells of the control group. FIG. 3B
shows a Flow Cytometry pattern of H1975 cells having been treated
with 1 .mu.M of the compound of Formula (IIa). FIG. 3C shows a Flow
Cytometry pattern of H1975 cells having been treated with 2 .mu.M
of the compound of Formula (IIa). FIG. 3D shows a Flow Cytometry
pattern of H1975 cells having been treated with 3 .mu.M of the
compound of Formula (IIa). FIG. 3E shows a Flow Cytometry pattern
of H1975 cells having been treated with 4 .mu.M of the compound of
Formula (IIa).
FIG. 3F shows the rate of apoptosis of H1975 cells having been
treated with 1 .mu.M, 2 .mu.M, 3 .mu.M or 4 .mu.M of the compound
of Formula (IIa) of the present invention compared to the control
group.
FIGS. 4A, 4B, 4C, and 4D show Flow Cytometry patterns of H1650
cells having been treated with 4 .mu.M of compound of Formula (IIa)
in the presence or absence of N-acetylcystein (NAC) compared to
treatment with NAC and the control group. FIG. 4A shows a Flow
Cytometry pattern of H1650 cells of the control group. FIG. 4B
shows a Flow Cytometry pattern of H1650 cells having been treated
with NAC. FIG. 4C shows a Flow Cytometry pattern of H1650 cells
having been treated with 4 .mu.M of the compound of Formula (IIa)
in the presence of NAC. FIG. 4D shows a Flow Cytometry pattern of
H1650 cells having been treated with 4 .mu.M of the compound of
Formula (IIa) in the absence of NAC.
FIG. 4E shows the rate of apoptosis of H1650 cells having been
treated with 4 .mu.M of the compound of Formula (IIa) in the
presence or absence of NAC compared to the control group.
FIGS. 5A, 5B, 5C, and 5D show Flow Cytometry patterns of H1975
cells having been treated with 4 .mu.M of compound of Formula (IIa)
in the presence or absence of N-acetylcystein (NAC) compared to
treatment with NAC and the control group. FIG. 5A shows a Flow
Cytometry pattern of H1975 cells of the control group. FIG. 5B
shows a Flow Cytometry pattern of H1975 cells having been treated
with NAC. FIG. 5C shows a Flow Cytometry pattern of H1975 cells
having been treated with 4 .mu.M of the compound of Formula (IIa)
in the presence of NAC. FIG. 5D shows a Flow Cytometry pattern of
H1975 cells having been treated with 4 .mu.M of the compound of
Formula (IIa) in the absence of NAC.
FIG. 5E shows the rate of apoptosis of H1975 cells having been
treated with 4 .mu.M of the compound of Formula (IIa) in the
presence or absence of NAC compared to the control group.
FIG. 6 refers to a western blot and shows the expression of cleaved
caspase-3 and cleaved PARP being indicators of apoptosis, wherein a
control group and H1650 cells treated with 4 .mu.M of the compound
of Formula (IIa) for 24 h with or without 10 mM NAC are shown.
FIG. 7 refers to a western blot and shows the expression of cleaved
caspase-3 and cleaved PARP being indicators of apoptosis, wherein a
control group and H1975 cells treated with 4 .mu.M of the compound
of Formula (IIa) for 24 h with or without 10 mM NAC are shown.
FIG. 8 refers to a western blot and shows the expression of EGFR,
phosphorylated EGFR as activated form of EGFR (tyrosine
phosphorylation sites 1068 and 1173 related with EGFR activation,
and tyrosine 1045 associated with EGFR degradation) and c-Cb1
assumed to downregulate EGFR expression, wherein a control group
and H1975 cells treated with 1 .mu.M, 2 .mu.M, 3 .mu.M and 4 .mu.M
of the compound of Formula (IIa) are shown.
DETAILED DESCRIPTION OF INVENTION
The following preparations and examples are given to enable those
skilled in the art to more clearly understand and to practice the
present invention. They should not be considered as limiting the
scope of the invention, but merely as being illustrative and for
representing preferred embodiments thereof. Those skilled in the
art will appreciate that the invention described herein is
susceptible to variations and modifications other than those
specifically described. The invention includes all such variations
and modifications. The invention also includes all steps and
features referred to or indicated in the specification,
individually or collectively, and any and all combinations of the
steps or features.
The technical terms used in the present patent application have the
meaning as commonly understood by a respective skilled person
unless specifically defined otherwise.
As used herein, "comprising" means including the following elements
but not excluding others. "Essentially consisting of" means that
the material consists of the respective element along with usually
and unavoidable impurities such as side products and components
usually resulting from the respective preparation or method for
obtaining the material such as traces of further components or
solvents. "Consisting of" means that the material solely consists
of, i.e. is formed by the respective element.
The present invention provides a hydroxynaphthoquinone compound for
use in a method for treating EGFR-dependent NSCLC in a subject in
need thereof. More specifically, the present invention, in a first
aspect, refers to a method of treating a subject suffering from
EGFR-dependent NSCLC comprising administering an effective amount
of a hydroxynaphthoquinone compound to the subject. The cancer is,
in particular, an adenocarcinoma.
The term "EGFR-dependent" (or EGFR-positive) as used within this
patent application refers to a cancer comprising cancer cells
harboring an abnormality in the EGFR gene. An abnormality in the
EGFR gene results from a mutation such as due to a substitution, in
particular missense substitution, insertion or deletion within the
exons 18 to 21 encoding a portion of the EGFR kinase domain, which
usually results in an increased kinase activity of EGFR, leading to
hyperactivation of downstream pro-survival signaling pathways. In
particular, the mutations comprise at least one of an exon 19
deletion or substitution, exon 20 insertion or substitution and/or
an exon 21 substitution, in particular at least one of exon 19
deletion and/or an exon 20 substitution. In more preferred
embodiments, the abnormality in EGFR gene means at least one
mutation selected from E746-A750del deletion in exon 19, L747S
substitution in exon 19, D761Y substitution in exon 19, T790M
substitution in exon 20, D770_N771 insertion in exon 20, V769L
substitution in exon 20, S7681 substitution in exon 20, T854A
substitution in exon 21, L858R substitution in exon 21 and/or A871E
substitution in exon 21, in particular at least one mutation
selected from E746-A750del in exon 19 and/or T790M substitution in
exon 20. In most preferred embodiments, at least two mutations of
EGFR gene are present, wherein one of them is a T790M substitution
in exon 20.
In a particular embodiment, the mutation comprises at least one
mutation of L747S substitution in exon 19, D761Y substitution in
exon 19, T790M substitution in exon 20, D770_N771 insertion in exon
20, V769L substitution in exon 20, S7681 substitution in exon 20,
T854A substitution in exon 21 and/or A871E substitution in exon
21.
Preferably, the abnormality in EGFR gene is associated with a
detectable increase in EGFR kinase activity. An "increased kinase
activity" of EGFR kinase means an expression of EGFR or an EGFR
kinase activity, which is at least 5% and preferably at least 10%
and further preferred at least 30% higher compared to a control
group, i.e. non-cancerous cells or cancerous cells without
abnormality in the EGFR gene. The skilled person is aware of
suitable methods for determining EGFR kinase expression or activity
such as with immunosorbent assays like with commercially available
kits usually with ELISA-based measurement. EGFR expression can be
measured, for example, by flow cytometry, real-time PCR, and
Western blotting.
Presence of an EGFR mutation can be confirmed by respective
molecular biological methods, wherein several methods are known to
the skilled person. Such tests are commonly performed using DNA or
RNA collected from biological samples, e.g., tissue biopsies, and
can be conducted by a variety of methods including, but not limited
to, sequence-specific PCR, direct DNA sequencing, hybridization
with allele-specific probes, enzymatic mutation detection, chemical
cleavage of mismatches or mass spectrometry. I.e. EGFR-dependent
NSCLC is in particular considered for being present, if at least
one of the above methods reveals an EGFR mutation.
Preferably, the EGFR-dependent NSCLC has an intrinsic or acquired
resistance against at least one EGFR inhibitor, preferably against
at least one of gefitinib, erlotinib and/or afatinib, more
preferably an intrinsic or acquired resistance at least against
gefitinib and/or erlotinib and further preferred at least against
gefitinib. This means that the cells with EGFR gene abnormality
preferably have an intrinsic or acquired resistance against at
least one EGFR inhibitor, most preferably at least against
gefitinib.
Such resistance can be caused by or follow from the EGFR mutation
as such, for example due to insertions or substitutions in exon 20,
in particular due to a T790M substitution in exon 20, so that the
EGFR inhibitors cannot provide therapeutic advantages. An acquired
resistance can also follow from, for example, MET gene
amplification encoding MET receptor tyrosine kinase and/or
fibroblast growth factor 2 (FGF2) and FGF receptor 1 (FGFR1)
induction, mitogen-activated protein kinase 1 (MAPK1)
amplification, mutations in downstream effector proteins to EGFR,
epithelial-to-mesenchymal transition and small-cell transformation.
The resistance against at least one EGFR inhibitor, in particular
at least against erlotinib and/or gefitinib, is preferably caused
by at least one of an EGFR mutation, MET gene amplification and/or
FGF2 and FGFR1 induction. Such EGFR inhibitor resistance can be
detected in a subject, tissue, or cell by administering to a
subject, tissue or cell an EGFR inhibitor and determining its
activity such as the induction of cell death, the inhibition of the
proliferation of cancer cells or the activation of EGFR such as one
or more of the phosphorylation of EGFR or its signaling proteins
like p-Akt, p-MEK1, p-ERK1/2, p-GSK-3.alpha./.beta., p-p70S6K, or
p-p90RSK compared to a control sample of the same cells or tissue
without treatment with the EGFR inhibitor and/or compared to a
reference sample, namely cells or tissue of the same cell or tissue
type or a subject that do not have EGFR inhibitor resistance. This
can be carried out by methods known to the skilled person like
phosphoprotein assays, cell viability measurement with MTT assays
or Western Blotting or the like.
In particular, a cell, tissue or subject is considered for being
resistant against an EGFR inhibitor, if the inhibitory effect of
the EGFR inhibitor on the activation of EGFR as measured by means
of phosphorylated EGFR or phosphorylated signaling proteins
downstream to EGFR is significantly lower compared to the
inhibitory effect of the EGFR inhibitor in the reference sample, in
particular the inhibitory effect on phosphorylated EGFR or
phosphorylated signaling proteins is at least 50% reduced compared
to the inhibitory effect of the EGFR inhibitor in the reference
sample, in particular no significant effect of the EGFR inhibitor
can be seen compared to the control sample. Another example for
verifying resistance against EGFR inhibitors are commercially
available caspase assays like caspase3/caspase7 luminescent assay
determining caspase cleavage and apoptosis, wherein the cell,
tissue or subject is resistant against an EGFR inhibitor, if the
effects of the EGFR inhibitor on the caspase3/7 activity measured
are lower than in the reference sample, preferably at most 50% of
the caspase activity compared to the reference sample and in
particular if no significant effect on the caspase activity is
measured compared to the control sample. In other embodiments,
cells are resistant against an EGFR inhibitor, if the IC.sub.50
value measured by means of an MTT assay on the cells or tissue is
at least 5-times, in particular at least 10-times, increased
compared to the IC.sub.50 measured in the reference sample.
The cancer is preferably an adenocarcinoma. The terms "cancer" and
"cancerous" refer to or describe a physiological condition in
subjects in which a population of cells are characterized by
unregulated cell growth. The term "tumor" simply refers to a mass
being of benign (generally harmless) or malignant (cancerous)
growth.
The method of the present invention comprises administering an
effective amount of a compound or a pharmaceutically acceptable
salt, solvate or anhydrate thereof to a subject. The subject can be
a human or animal, in particular the subject is a mammal and
further preferred a human. In preferred embodiments of the present
invention, the subject is a mammal, in particular a human, having
an abnormality in EGFR gene and with intrinsic or acquired
resistance against at least one of gefitinib, erlotinib and/or
afatinib, in particular intrinsic or acquired resistance at least
against gefitinib and/or erlotinib, which abnormality in EGFR gene
includes at least one of an exon 19 deletion or substitution, exon
20 insertion or substitution and/or an exon 21 substitution, in
particular at least one of E746-A750del deletion in exon 19, L747S
substitution in exon 19, D761Y substitution in exon 19, T790M
substitution in exon 20, D770_N771 insertion in exon 20, V769L
substitution in exon 20, S7681 substitution in exon 20, T854A
substitution in exon 21, L858R substitution in exon 21 and/or A871E
substitution in exon 21, more preferably at least one of
E746-A750del deletion in exon 19 and/or T790M substitution in exon
20. In a particular embodiment, the mutation comprises at least one
of L747S substitution in exon 19, D761Y substitution in exon 19,
T790M substitution in exon 20, D770_N771 insertion in exon 20,
V769L substitution in exon 20, S7681 substitution in exon 20, T854A
substitution in exon 21 and/or A871E substitution in exon 21.
The compound of the present invention is a hydroxynaphthoquinone
compound, namely a hydroxy-1,4-naphthoquinone compound, also named
hydroxy-4a,8a-dihydronaphthalene-1,4-dione, and more specifically a
4a,8a-dihydro-5,8-dihydroxynaphthalene-1,4-dione compound.
Hydroxy-1,4-naphthoquinones are compounds which are, for example,
known from plants and microorganism representing secondary
metabolites.
The compound of the present invention has a structure of Formula
(I) or is any pharmaceutically acceptable salt, anhydrate or
solvate thereof:
##STR00007##
R is selected from H, OH,
##STR00008##
Also contemplated by the present invention are enantiomers and
their mixtures and racemates of the compounds of Formula (Ia) and
Formula (Ib) comprising a stereogenic carbon atom in position 1'.
Namely, Formula (I) includes the enantiomers of Formula (Ia) and
(Ib), their mixtures and the racemate:
##STR00009##
In an embodiment of the present invention, the compound is the
enantiomer of Formula (Ia), wherein R is as defined above. In
another embodiment of the present invention, the compound is the
enantiomer of Formula (Ib), wherein R is as defined above. In still
another embodiment of the present invention, the compound is a
mixture of the enantiomer of Formula (Ia) and of Formula (Ib) or a
racemate thereof, wherein R is as defined above.
The compounds of Formula (I) can be prepared by suitable methods,
such as by chemical synthesis, by extraction from plant materials
or from suitable cell tissue cultures. Methods for separating
enantiomers are known to the skilled person, too, like chiral
chromatography. The compound of Formula (I), is, for example,
obtainable from plants of the Boraginaceae family such as, for
example, from the Arnebia genus, Alkanna genus or Lithospermum
genus and including, for example, Arnebia euchroma, Arnebia
guttata, Arnebia hispidissima, Arnebia nobilis, Arnebia tinctoria,
Arnebia densiflora, Alkanna tinctoria, Lithospermum arvense or
Lithospermum erythrorhizon. The compound of Formula (I) can in
particular be isolated from the roots of the above-mentioned
plants, more preferably from the roots of Lithospermum
erythrorhizon. Methods for extraction can include steps of:
Optionally drying the plant material, and/or cutting, shredding,
milling and/or pulverizing the plant material; Subjecting the plant
material to a solvent extraction with an extraction solvent, for
example by utilizing a Soxhlet extractor, which extraction solvent
can be, for example, an alkane line n-hexane or petroleum ether, a
halogenated alkane like dichloromethane or chloroform, an ester
like ethyl acetate or an alcohol like methanol or mixtures thereof;
Removing the extraction solvent for obtaining a crude extract; and
Optionally separating compounds from the crude extract and
purifying the compounds.
As used herein, the term "solvate" refers to a complex of variable
stoichiometry formed by a solute, i.e. compound of Formula (I), and
a solvent. If the solvent is water, the solvate formed is a
hydrate. As used herein, the term "anhydrate" means any compound
free of the water of hydration, as would be understood in the art.
Suitable pharmaceutically acceptable salts are those which are
suitable to be administered to subjects, in particular mammals such
as humans and can be prepared with sufficient purity and used to
prepare a pharmaceutical composition. The terms enantiomers and
racemates are known to the skilled person.
In especially preferred embodiments, the compound is a compound of
Formula (II):
##STR00010##
The compound includes the enantiomers, their mixtures or is a
racemate of the compounds of Formula (IIa) and (IIb):
##STR00011##
In one preferred embodiment, the compound is a compound of Formula
(IIa) or any pharmaceutically acceptable salt, solvate or anhydrate
thereof, which compound is also named shikonin and represents the
R-enantiomer. In alternative embodiments, the compound is a
compound of Formula (IIb), or any pharmaceutically acceptable salt,
solvate or anhydrate thereof, also named alkannin representing the
S-enantiomer.
The inventors conclude that the compound of Formula (I), in
particular the compound of Formula (IIa), is especially suitable to
inhibit EGFR kinase activity in EGFR-dependent NSCLC in particular
with intrinsic or acquired resistance against EGFR inhibitors. Said
compound is suitable to induce apoptosis accompanied by an enhanced
generation of oxidative reactive species (ROS), too, in
EGFR-dependent NSCLC. Such interactions are able to allow for
sufficiently and exceptionally inhibiting the EGFR
transautophosphorylation and anti-apoptotic and growth signaling
downstream to EGFR.
As further shown below, respective data with EGFR-dependent
adenocarcinoma cell lines with gefitinib resistance further confirm
that compound of Formula (IIa) is especially effective in
inhibiting EGFR kinase activity. The compound of Formula (IIa)
proved to be highly cytotoxic and selective to NSCLC cells. In
particular, the compound of Formula (IIa) proved to exceptionally
induce apoptosis and suppress the transautophosphorylation of EGFR
kinase while making use of EGFR-dependent NSCLC cell lines with
gefitinib resistance.
The expression "effective amount" generally denotes an amount
sufficient to produce therapeutically desirable results, wherein
the exact nature of the result varies depending on the specific
disorder which is treated. When the disorder is cancer, the result
is usually an inhibition or suppression of the proliferation of the
cancer cells, a reduction of cancerous cells or the amelioration of
symptoms related to the cancer cells, in particular inhibition,
reduction or prevention of the proliferation of the cancer cells or
induction of cell death, i.e. apoptosis of the cancer cells.
The effective amount of the compound of Formula (I) may depend on
the species, body weight, age and individual conditions and can be
determined by standard procedures such as with cell cultures or
experimental animals. The concentration of the compound of Formula
(I), such as the compound of Formula (IIa), effective for treating
the subject may, for example, be at least 1 .mu.M, preferably at
least 2 .mu.M, in particular at least 3 .mu.M and further preferred
at least 4 .mu.M.
The compound of Formula (I) has an IC.sub.50 on EGFR-dependent
NSCLC cells of at most 10 .mu.M, preferably at most 5 .mu.M and in
particular at most 4 .mu.M and an IC.sub.50 on non-cancerous lung
cells being at least 2 times higher, more preferably 3 times higher
than the IC.sub.50 on EGFR-dependent NSCLC cells.
In embodiments of the present invention, the disease is
EGFR-dependent NSCLC with intrinsic or acquired resistance at least
against one of gefitinib, erlotinib and/or afatinib, in particular
at least against gefitinib and/or erlotinib, and the compound has
an IC.sub.50 on said NSCLC cells of at most 5 .mu.M and an
IC.sub.50 on non-cancerous lung cells being at least 2 times
higher, preferably at least 3 times higher than the IC.sub.50 on
the NSCLC cells harboring an abnormality in the EGFR gene.
The method of the present invention may further include steps
carried out before administering the compound of Formula (I), such
as compound of Formula (IIa), to the subject comprising: Obtaining
a sample, in particular cancer cells, from the subject; Testing
said sample for the EGFR kinase activity and/or identifying at
least one EGFR mutation as abnormality in the EGFR gene; Optionally
correlating the EGFR kinase activity and/or abnormality in the EGFR
gene with outcome and if conditions are met, administrating the
compound of Formula (I), in particular compound of Formula (IIa),
to said subject.
According to the invention is also the compound of Formula (I), in
particular the compound of Formula (IIa), for use in the treatment
of EGFR-dependent NSCLC, in particular EGFR-dependent NSCLC with
intrinsic or acquired resistance against an EGFR inhibitor such as
selected from at least one of gefitinib, erlotinib and/or afatinib,
in particular with intrinsic or acquired resistance at least
against gefitinib and/or erlotinib. The compound of Formula (I), in
particular the compound of Formula (IIa), can be used in an
effective amount for treating a human. Another aspect of the
invention refers to the use of the compound of Formula (I), in
particular the compound of Formula (IIa), for preparing a
medicament for treatment of EGFR-dependent NSCLC, in particular
EGFR-dependent NSCLC with intrinsic or acquired resistance against
an EGFR inhibitor such as selected from at least one of gefitinib,
erlotinib and/or afatinib, in particular with intrinsic or acquired
resistance at least against gefitinib and/or erlotinib.
The compound of Formula (I) may be used in combination with other
therapeutic compounds, preferably therapeutic compounds which are
used for treating NSCLC.
In still another aspect, the present invention refers to a method
of inhibiting EGFR kinase activity in NSCLC cells harboring an
abnormality in the EGFR gene by a compound of Formula (I), i.e.
comprising administering an effective amount of the compound of
Formula (I) or a pharmaceutically acceptable salt, solvate or
anhydrate thereof:
##STR00012##
R is selected from H, OH,
##STR00013## to a subject suffering from EGFR-dependent NSCLC.
The compound, in particular, is a compound of Formula (II), more
preferably of Formula (IIa):
##STR00014##
The EGFR-dependent NSCLC is in particular EGFR-dependent NSCLC with
intrinsic or acquired resistance against at least one EGFR
inhibitor such as selected from at least one of gefitinib,
erlotinib and/or afatinib, further preferred intrinsic or acquired
resistance at least against gefitinib and/or erlotinib. In one
embodiment of the present invention, the disease is an
adenocarcinoma. This means that the NSCLC cells harboring an
abnormality in the EGFR gene, in particular have an intrinsic or
acquired resistance against at least one EGFR inhibitor.
The subject can be a human or animal, in particular the subject is
a mammal and further preferred a human. The abnormality in EGFR
gene preferably means at least one of an exon 19 deletion or
substitution, exon 20 insertion or substitution and/or an exon 21
substitution, in particular at least one of E746-A750del deletion
in exon 19, L747S substitution in exon 19, D761Y substitution in
exon 19, T790M substitution in exon 20, D770_N771 insertion in exon
20, V769L substitution in exon 20, S7681 substitution in exon 20,
T854A substitution in exon 21, L858R substitution in exon 21 and/or
A871E substitution in exon 21, more preferably at least one of
E746-A750del deletion in exon 19 and/or T790M substitution in exon
20. In a particular embodiment, the abnormality in the EGFR gene
means at least one of L747S substitution in exon 19, D761Y
substitution in exon 19, T790M substitution in exon 20, D770_N771
insertion in exon 20, V769L substitution in exon 20, S7681
substitution in exon 20, T854A substitution in exon 21 and/or A871E
substitution in exon 21.
The compound of Formula (I) has an IC.sub.50 on the NSCLC cells
with the abnormality in the EGFR gene of at most 10 .mu.M,
preferably at most 5 .mu.M and in particular at most 4 .mu.M and an
IC.sub.50 on non-cancerous lung cells being at least 2 times
higher, more preferably 3 times higher than the IC.sub.50 on the
NSCLC cells.
The compound of the present invention may be administered in the
methods of the present invention described above in form of a
composition comprising the compound of Formula (I), in particular
the compound of Formula (IIa), or a salt, solvate or anhydrate
thereof. The composition further comprises excipients such as
pharmaceutically acceptable excipients, a buffer, salt, water or a
combination thereof. In particular the composition is a
pharmaceutical composition comprising the compound of Formula (I),
in particular the compound of Formula (IIa), or a pharmaceutically
acceptable salt, solvate or anhydrate thereof. Said pharmaceutical
composition further comprises pharmaceutically acceptable
excipients and may additionally contain further active ingredients,
in particular therapeutic compounds for treating NSCLC.
The skilled person is able to select suitable excipients depending
on the form of the pharmaceutical composition and is aware of
methods for manufacturing pharmaceutical compositions as well as
able to select a suitable method for preparing the pharmaceutical
composition depending on the kind of excipients and the form of the
pharmaceutical composition. The pharmaceutical composition
according to the invention can be present in solid, semisolid or
liquid form to be administered by an oral, rectal, topical,
parenteral or transdermal or inhalative route to a subject,
preferably a human.
Preferably, the pharmaceutically acceptable excipient is at least
one of a diluent, a filler, a binder, a disintegrant, a lubricant,
a coloring agent, a surfactant or a preservative. The present
invention also refers to the use of the composition such as the
pharmaceutical composition for inhibiting EGFR kinase activity in
subjects with EGFR-dependent cancer and/or NSCLC cells harboring an
abnormality in the EGFR gene, in particular EGFR-dependent NSCLC
and NSCLC cells with an abnormality in the EGFR gene, respectively,
and with intrinsic or acquired resistance against EGFR inhibitors
such as selected from at least one of gefitinib, erlotinib and/or
afatinib, in particular with intrinsic or acquired resistance at
least against gefitinib and/or erlotinib.
The present invention in another aspect refers to a method for
targeting NSCLC cells harboring an abnormality in EGFR gene
comprising the step of contacting said cells with a
hydroxynaphthoquinone compound of Formula (I) or a salt, solvate or
anhydrate thereof:
##STR00015##
R is selected from H, OH,
##STR00016##
The abnormality in EGFR gene, in particular, includes at least one
of an exon 19 deletion or substitution, exon 20 insertion or
substitution and/or an exon 21 substitution, in particular at least
one of E746-A750del deletion in exon 19, L747S substitution in exon
19, D761Y substitution in exon 19, T790M substitution in exon 20,
D770_N771 insertion in exon 20, V769L substitution in exon 20,
S7681 substitution in exon 20, T854A substitution in exon 21, L858R
substitution in exon 21 and/or A871E substitution in exon 21, more
preferably at least one of E746-A750del deletion in exon 19 and/or
T790M substitution in exon 20. In a particular embodiment, the
mutation comprises at least one of L747S substitution in exon 19,
D761Y substitution in exon 19, T790M substitution in exon 20,
D770_N771 insertion in exon 20, V769L substitution in exon 20,
S7681 substitution in exon 20, T854A substitution in exon 21 and/or
A871E substitution in exon 21. More preferably, the NSCLC cells
harboring an abnormality in the EGFR gene have an intrinsic or
acquired resistance against at least one of gefitinib, erlotinib
and/or afatinib, in particular at least against gefitinib and/or
erlotinib. The EGFR-dependent NSCLC cells are preferably from an
adenocarcinoma.
Preferably, the proliferation of the NSCLC cells is inhibited,
reduced or prevented or apoptosis of the cancer cells is induced,
more preferably apoptosis of the NSCLC cells is induced. The
skilled person is aware of methods for verifying such effects such
as with cell viability measurement by means of a MTS proliferation
assay, a MTT assay, Caspase-3 assay or by determination of the
apoptosis rate by means of Annexin V flow cytometry
measurement.
Preferably, the NSCLC cells are contacted with the compound of
Formula (I) for at least 10 h, more preferably for at least 12 h
such as for about 24 h. The compound of Formula (I) is preferably
used for contacting the cells in a concentration of at least 1
.mu.M, more preferably of at least 2 .mu.M and especially
preferably at least 3 .mu.M and further preferred of at least 4
.mu.M. The NSCLC cells contacted with the compound of Formula (I)
may comprise between 1.0.times.10.sup.3 cells and
1.0.times.10.sup.6 cells, in particular about 1.0.times.10.sup.6
cells.
The compound of Formula (I) has an IC.sub.50 on the NSCLC cells
harboring an abnormality in the EGFR gene of at most 10 .mu.M and
an IC.sub.50 on non-cancerous lung cells being at least 2 times
higher, preferably at least 3 times higher than the IC.sub.50 on
said NSCLC cells.
In embodiments of the present invention, the abnormality in EGFR
gene in particular includes at least one of E746-A750del deletion
in exon 19 and/or T790M substitution in exon 20, and the compound
has an IC.sub.50 on the NSCLC cells harboring an abnormality in the
EGFR gene of at most 5 .mu.M and an IC.sub.50 on non-cancerous lung
cells being at least 3 times higher than the IC.sub.50 on said
NSCLC cells. More preferably, the NSCLC cells harboring an
abnormality in the EGFR gene have an intrinsic or acquired
resistance against at least one of gefitinib, erlotinib and/or
afatinib, in particular against at least gefitinib and/or
erlotinib. The NSCLC cells harboring an abnormality in the EGFR
gene are preferably from an adenocarcinoma.
Still more preferably, the compound used for contacting said NSCLC
cells harboring an abnormality in the EGFR gene is a compound
having Formula (II) or a salt, solvate or anhydrate thereof:
##STR00017## and is in particular used in a concentration of at
least 2 .mu.M.
Especially preferably, the compound used for contacting the NSCLC
cells harboring an abnormality in the EGFR gene is a compound
having Formula (IIa):
##STR00018## wherein the concentration of compound (IIa) for
contacting said cells is at least 2 .mu.M, in particular at least 3
.mu.M and further preferred at least 4 .mu.M, wherein the cells are
preferably contacted with the compound for at least 12 h.
EXAMPLES
The efficiency of the compound of Formula (IIa) as inhibitor of
EGFR has been evaluated. First of all, the cytotoxic properties of
the compound of Formula (IIa) with regard to cells with abnormality
in the EGFR gene have been analyzed. Secondly, the induction of
apoptosis has been evaluated and the effects on the EGFR
phosphorylation and anti-apoptotic and growth signaling pathways
downstream to EGFR.
In the below examples, differences are analyzed by one-way ANOVA.
All statistical analyses are carried out using Graph Prim5.0.
Values of P<0.05 were considered statistically significant.
Example 1
Cytotoxicity of the Compound of Formula (IIa) on NSCLC Cells with
Abnormality in the EGFR Gene and Non-Cancerous Lung Epithelial
Cells
To show the highly cytotoxic properties of the present compound of
Formula (IIa), H1650, HCC827 and H1975 NSCLC cells and
non-cancerous lung fibroblast cells (CCD-19LU) were treated with
the compound of Formula (IIa) and respective effects were observed.
H1650 cells are adenocarcinoma cells harboring an E746-A750del
deletion in exon 19 and other driver mutation genes which lead to a
resistance against gefitinib. HCC827 cells are adenocarcinoma cells
harboring high level EGFR amplification and an E746-A750del
deletion in exon 19 without gefitinib-resistance. H1975 cells are
adenocarcinoma cells harboring L858R substitution in exon 21 and a
T790M substitution in exon 20 which is directly associated with
resistance against gefitinib. The cells were obtained from the
American Type Culture Collection (ATCC) and cultured in environment
of 5% CO.sub.2 at 37.degree. C. in RPMI-1640 medium supplemented
with 10% fetal bovine serum (FBS), 100 units/mL penicillin, and 100
.mu.g/mL streptomycin. The compound of Formula (IIa) was dissolved
in DMSO. Using a MTT assay, 4000 cells/well of an adenocarcinoma
cell type or CCD-19LU cells were seeded on 96-well plates, cultured
overnight for cell adhesion, and treated with DMSO or various
concentrations of the compound of Formula (IIa) for 24 h. Three
independent tests were performed. 10 .mu.L of MTT (5 mg/mL; Sigma)
were added to each well, and incubation continued for another 4 h.
Then the dark blue crystals were dissolved in 100 .mu.L of the
resolved solution (10% SDS and 0.1 mM HCL). The absorbance was
measured at 570 nm by a microplate reader (Tecan, Morrisville,
N.C., USA).
The cell viability was calculated relative to untreated controls,
with results based on at least three independent experiments. The
MTT assay confirmed that the compound of Formula (IIa) shows
selectively cytotoxic effects on NSCLC cells harboring an
abnormality in the EGFR gene with IC.sub.50 values given in table 1
while it shows much lower cytotoxicity on non-cancerous lung
fibroblast cells (CCD-19LU) after 24 h treatment (FIG. 1A to FIG.
1D and table 1). The compound of Formula (IIa), thus, proved to be
highly selectively towards the NSCLC cells.
TABLE-US-00001 TABLE 1 IC.sub.50 of the compound of Formula (IIa)
Cell lines IC.sub.50 (.mu.M) H1650 3.849 .mu.M .+-. 0.354 HCC827
3.511 .mu.M .+-. 0.375 H1975 2.635 .mu.M .+-. 0.192 CCD-19LU 12.16
.mu.M .+-. 1.00
Example 1B
Anticancer Effect of the Compound of Formula (IIa) Through Inducing
Apoptosis in Gefitinib-Resistant NSCLC Cells with Abnormality in
the EGFR Gene
Apoptosis assay was performed on gefitinib-resistant H1650 and
H1975 cells. The cells (1.0.times.10.sup.5 cells/well) were allowed
to attach to a 6-well plate for 24 h, and the cells were treated
with the various concentrations of the compound of Formula (IIa)
for additional 24 h. At the end of incubation, the cells were
harvested by trypsinization and washed twice with ice-cold PBS.
After centrifugation and removal of the supernatants, cell pellets
were resuspended in 100 .mu.L 1.times.Annexin-binding buffer, 2
.mu.L Annexin-V FITC and 2 .mu.L PI (100 .mu.g/ml) were added and
incubated in the dark at room temperature for 15 min before further
addition of 400 .mu.L of 1.times.Annexin-binding buffer. The
stained cells were analyzed quantitatively using a flow cytometer
(BD Biosciences, San Jose, Calif., USA). Data were analyzed by Flow
Jo software. FIG. 2A to 2E show fluorescence images of H1650 cells
and FIG. 3A to 3E show fluorescence images of H1975 cells having
been treated with the compound of Formula (IIa) at 1 .mu.M, 2
.mu.M, 3 .mu.M and 4 .mu.M; and DMSO (control, negative
control).
It is evident, that the compound of Formula (IIa) significantly
induced apoptosis of the gefitinib-resistant NSCLC cells in a
concentration-dependent manner.
Example 1C
Compound of Formula (IIa) Enhances Reactive Oxygen Species (ROS)
Generation in Gefitinib-Resistant NSCLC Cells with Abnormality in
the EGFR Gene
Apoptosis assay and analysis with flow cytometer was performed as
described in Example 1B with H1650 and H1975 cells and treatment
with 4 .mu.M of the compound of Formula (IIa) for 30 min in the
presence or absence of N-acetylcystein (NAC) or treatment with DMSO
(control, negative control). FIG. 4A to 4D show fluorescence images
of H1650 cells and FIG. 5A to 5D show fluorescence images of H1975
cells.
ROS generation was considered as the direct cause of apoptosis
induced by the compound of Formula (IIa). After 30 min treatment of
the H1650 and H1975 cells, the intensity of ROS increased more than
10-fold. NAC, an inhibitor of ROS, completely blocked the apoptosis
induced by the compound of Formula (IIa).
Example 1D
Compound of Formula (IIa) Leads to a Reduced Caspase and PARP
Activation in Gefitinib-Resistant NSCLC Cells with Abnormality in
the EGFR Gene
The H1650 or H1975 cells were planted on 6-well plates, allowed to
attach for 24 h, and treated with 4 .mu.M of the compound of
Formula (IIa) with or without NAC (10 mM) for 24 h. Cells were
washed twice with cold PBS then lysed in RIPA lysis buffer
containing protease and phosphatase inhibitors. Protein
concentration of the cell lysates was measured using the Bio-Rad
protein Assay kit (Bio-Rad, 7 Philadelphia, Pa., USA). After
equalizing the protein concentrations of the samples, 5.times.
laemmli buffer was added and the samples were boiled at 100.degree.
C. for 5 min. Equal amounts of protein samples (30 .mu.g) were
subjected to SDS-PAGE of a 10% gel. The separated proteins were
transferred to a nitrocellulose (NC) membrane, which was then
exposed to 5% non-fat dried milk in TBS containing 0.1% Tween (0.1%
TBST) for 1 h at room temperature, followed by overnight incubation
at 4.degree. C. with primary antibodies. After washing three times
by TBST (5 mins/time), the membranes were incubated for 1 h at room
temperature with secondary fluorescent antibodies (1:10000
dilutions) to rabbit or mouse. The signal intensity of the
membranes was detected by an LI-COR Odessy scanner (Belfast, Me.,
USA).
As illustrated in FIG. 6 and FIG. 7, the compound of Formula (IIa)
lead to an increased apoptosis indicated by the increase in cleaved
Caspase-3 and cleaved Poly(ADP-ribose) Polymerase (PARP) as
downstream effector to caspases. As evident, the apoptosis was
blocked by NAC.
Example 1E
Suppression of EGFR Phosphorylation Signaling Pathways by the
Compound of Formula (IIa) in Gefitinib-Resistant NSCLC Cells with
Abnormality in the EGFR Gene
H1975 cells were planted on 6-well plate, allowed to attach for 24
h, and treated with the various concentrations of the compound of
Formula (Ic) for 2 h. Cells were washed twice with cold PBS then
lysed in RIPA lysis buffer containing protease and phosphatase
inhibitors. Protein concentration of the cell lysates was measured
using the Bio-Rad protein Assay kit (Bio-Rad, 7 Philadelphia, Pa.,
USA). After equalizing the protein concentrations of the samples,
5.times. laemmli buffer was added and the samples were boiled at
100.degree. C. for 5 min. Equal amounts of protein samples (30
.mu.g) were subjected to SDS-PAGE of a 10% gel. The separated
proteins were transferred to a nitrocellulose (NC) membrane, which
was then exposed to 5% non-fat dried milk in TBS containing 0.1%
Tween (0.1% TBST) for 1 h at room temperature, followed by
overnight incubation at 4.degree. C. with primary antibodies. After
washing three times by TBST (5 mins/time), the membranes were
incubated for 1 h at room temperature with the secondary
fluorescent antibodies (1:10000 dilutions) to rabbit or mouse. The
signal intensity of the membranes was detected by an LI-COR Odessy
scanner (Belfast, Me., USA). Actin was used as the loading control
for normalization.
The compound of Formula (IIa) proved to suppress EGFR
phosphorylation and anti-apoptotic and growth signaling pathways
that are downstream to EGFR. This is evident from the results for
the tyrosine phosphorylation site 1068 and 1173 related with EGFR
activation, and for tyrosine 1045 associated with EGFR degradation.
C-Cb1 is related to degradation of EGFR, either. The results
illustrated in FIG. 8, thus, prove that the compound of Formula
(IIa) inhibits EGFR a, its transautophosphorylation and, thus,
signaling pathways downstream to EGFR.
* * * * *